Various mechanisms have been used to drive and index spiral arrays of individual film photographs, and these mechanisms have either been costly to produce or complicated to operate and control and have also lacked simple mechanisms for precision indexing and advancement of a spiral array of individual photographs for successive exposure thereof and projection thereof onto a viewing surface such as a screen or the like. Many of the prior art mechanisms have been devoted to short run movies and are not particularly adapted for use in displaying individual slides as they relate to recorded commentaries directed to the subject matter displayed by individual photographs.